Erin Letovsky, Ian E Myers, Alexandra Canepa, Declan J McCabe
BIOS 83 (2), 47-55, (1 July 2012) https://doi.org/10.1893/0005-3155-83.2.47
KEYWORDS: Artificial substrate, rarefaction, biological monitoring
Differences among sampling techniques are of crucial importance when interpreting the results of aquatic biomonitoring studies. We compared two commonly used variations of the kick sampling technique with the Hester-Dendy (multi-plate substrate) technique in an urban impacted stream. The effect of sample pooling on data interpretation was also examined. Hand scrubbing and disrupting substrates yielded more hydropsychid caddisflies than either kick sampling or Hester-Dendy samples. Total macroinvertebrate abundance, species richness, and Shannon's diversity (H') were all lower in Hester-Dendy samples than in samples taken by kick sample or by hand scrubbing substrates. Species richness pooled within sampling technique was highest in kick samples and lowest in Hester-Dendy samples. Richness of Ephemeroptera, Plecoptera, and Trichoptera (EPT) pooled among sampling techniques was higher in Hester-Dendy samples than in either kick samples or substrate-scrubbed samples. Relatively subtle differences among sampling technique and data processing have the potential to influence interpretation of biomonitoring studies. In particular, differential success in sampling hydropsychid caddisflies and other EPT taxa can influence a large number of benthic indices. Finally, samples pooled and rarified can illuminate differences detectable only at higher abundance levels.